1. Protein separation SDS-PAGE molecular weight markers stain intensity estimation 2. Serum protein analysis albumin globulin α1 α2 β γ electrophoresis lanes 3. Immunoglobulin spike monoclonal gammopathy multiple myeloma diagnostic evidence 4. Decreased albumin increased γ-globulin liver disease nephrotic syndrome inflammation 5. Densitometry curve interpretation peak area quantification protein concentration 6. Case study gel image evaluation serum component abnormalities clinical implications